stratum

[ strey-tuhm, strat-uhm ]

noun

, plural stra·ta [strey, -t, uh, strat, -, uh], stra·tums.

1. a layer of material, naturally or artificially formed, often one of a number of parallel layers one upon another:

   a stratum of ancient foundations.

2. one of a number of portions or divisions likened to layers or levels:

   an allegory with many strata of meaning.

3. Geology. a single bed of sedimentary rock, generally consisting of one kind of matter representing continuous deposition.
4. Biology. a layer of tissue; lamella.
5. Ecology. (in a plant community) a layer of vegetation, usually of the same or similar height.
6. a layer of the ocean or the atmosphere distinguished by natural or arbitrary limits.
7. Sociology. a level or grade of a people or population with reference to social position, education, etc.:

   the lowest stratum of society.

8. Linguistics. (in stratificational grammar) a major subdivision of linguistic structure. Compare level ( def 17 ).

stratum

/ ˈstrɑːtəm /

noun

1. usually plural any of the distinct layers into which sedimentary rocks are divided
2. biology a single layer of tissue or cells
3. a layer of any material, esp one of several parallel layers
4. a layer of ocean or atmosphere either naturally or arbitrarily demarcated
5. a level of a social hierarchy that is distinguished according to such criteria as educational achievement or caste status

stratum

/ strā′təm,străt′əm /

, Plural strata

1. A layer of sedimentary rock whose composition is more or less the same throughout and that is visibly different from the rock layers above and below it.
2. A layer of tissue, as of the skin or another organ.

Usage Note

Strata, historically the plural of stratum, is occasionally used as a singular: The lowest economic strata consists of the permanently unemployable. Less frequently, a plural stratas occurs: Several stratas of settlement can be seen in the excavation. At present, these uses are not well established, and they are condemned in usage guides. Strata may eventually become part of a group of borrowed plurals that are now used as singulars in English, such as agenda and candelabra, but it is not yet in that category. agenda, criterion, media, phenomena.

Derived Forms

• ˈstratal, adjective

Other Words From

• stratous adjective

Word History and Origins

Origin of stratum¹

1590–1600; < Latin strātum literally, a cover, noun use of neuter of strātus, past participle of sternere to spread, strew, equivalent to strā- variant stem + -tus past participle suffix

Word History and Origins

Origin of stratum¹

C16: via New Latin from Latin: something strewn, from sternere to scatter

Example Sentences

According to exit polls, the only economic stratum that Harris clearly won was people with household incomes above $100,000.

From Salon

I imagine the average Lloyd Webber fan would be happy enough with conventional treatments, but there’s a whole other stratum of people — critics, sponsors, professional peers — who also need to be wowed in order to cultivate a sense of credibility and keep the brand relevant.

From New York Times

Mr. Trump’s memes seem to resonate with a stratum of American society that feels disaffected and maligned in a rapidly changing world.

From Salon

However, the recently developed technology is expected to allow long-term and high-quality EMG measurements as it uses a stretchable and adhesive conducting substrate integrated with microneedle arrays that can easily penetrate the stratum corneum without causing discomfort.

From Science Daily

The hard microneedles penetrate through the stratum corneum, which has high electrical resistance.

From Science Daily